Retractable Step

ABSTRACT

A retractable step for entering and exiting rail vehicles. The retractable step has a surface which can be walked upon and is configured to be extended in an essentially linear direction to bridge a gap between the rail vehicle and a platform. The retractable step includes a leading edge and has at least one sensor configured to prevent a collision with objects during an extension operation of the retractable step. The strip is movably connected to the retractable step and extends over an entire length L of the retractable step.

BACKGROUND AND SUMMARY

The present disclosure relates to a retractable step. A retractable stepis understood as meaning an entry aid for assisting the entering andexiting of vehicles, particularly rail vehicles. The retractable stephas a surface which can be walked upon being extended from the vehicleessentially in a linear direction in order to bridge the gap between thevehicle and the platform or the like.

Depending on the positioning between the vehicle box body and theplatform, the retractable step, generally toward the end of itsextension movement, comes into the region of the platform . There is therisk of it moving laterally into the essentially vertically extendingplatform wall. This problem is overcome by sensors in the region of theleading edge of the retractable step.

Another problem is that, in the case of an extended retractable step, achange in height of the retractable step may occur during the time thevehicle spends in the station. This may take place within a short periodby the suspension yielding, by the vehicle load changing as passengersget in and out, by the wind load stressing changing, and by more of thesame sort of reasons. The greatest possible change in height is definedhere by various parameters of the vehicle (type of suspension, positionof the stops, length of the lever arms of the retractable step relativeto the pivot axis, etc.) and is called maximum change in height below.The actual change in the height position within the context of thismaximum change in height may result in luggage or passengers becomingtrapped, or the retractable step being damaged if the retractable stepis correspondingly lowered. Since the objects at risk generally do notextend over the entire width of the retractable step and it cannot bepredicted in which region of the retractable step they are located,detection has hitherto been impossible and the risk of body parts orobjects becoming trapped or of the retractable step becoming damaged hashad to be accepted.

The present disclosure relates to a device with which it is possible tocarry out a detection of the above-mentioned type in a satisfactory andcost-effective manner.

According to the present disclosure, this is achieved in that a strip isconnected movably to the retractable step. The strip extends essentiallyover the entire length of the retractable step and, in the activatedstate, being located essentially under the front edge of the retractablestep. In addition, at least one sensor is provided which detects theposition of the strip and/or the force transmitted by the strip to theretractable step.

As a result, every impermissible approach toward the upper side of theplatform can be detected as can the imminent risk of an object or bodypart becoming trapped. The positioning of the strip makes it possible,during the extension of the retractable step, also to detect the space(detection space) in which, during a lowering operation, the retractablestep could move and thus makes it possible to safeguard it. An activatedstate is taken up by the strip at least during the extension of theretractable step.

The movable connection between strip and retractable step makes itpossible to bring the strip into the desired position, if appropriateautomatically, during the extension of the retractable step. Themonitoring of this position remains activated during the extension ofthe retractable step into its end position.

If a change in the position of the strip is detected, the extensionmovement is stopped and the retractable step is moved back by apredetermined length by which a safe distance from the object isensured. In addition, for example, an acoustic and/or optical alarmsignal may be emitted. Of course, a different reaction is possible ifthis is desired by the operator.

The strip itself may either execute an extension movement which isoblique with respect to the direction of extension of the retractablestep but is essentially linear. It may also execute a rotationalmovement and be swung out.

Depending in each case on the design and movement of the strip, a verywide variety of sensors, which can be designed as switches or straingauges or based on an electrodynamic or piezoelectric effect, aresuitable as the actual sensor. The sensors may be arranged eitherdirectly in the strip and measure the force between an underlyingsurface and the strip, or they are accommodated in the region of thebearings of the strip and measure the forces between the strip andretractable step, which forces may originate from the first-mentionedforces.

The transition of the strip from the passive position into the activeposition can take place by the dead weight of the strip, a slotted-guidemechanism and possibly a spring. Of course, it is also possible toprovide a motor drive.

In accordance with the present disclosure, if the retractable step is tobe retracted if a trapping risk is established, it is favorable that,during this retraction movement, the strip releases any objects alreadytrapped as rapidly as possible without further loading and does not trapand keep hold of them.

Other aspects of the present disclosure will become apparent from thefollowing descriptions when considered in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a front view of an embodiment of a retractable step,according to the present disclosure.

FIG. 2 shows a partial sectional view in the direction of the arrow IIof FIG. 1.

FIG. 3 shows a partial sectional view on an enlarged scale of anotherembodiment of a retractable step, according to the present disclosure.

FIG. 4 shows a partial sectional view of another embodiment of aretractable step, according to the present disclosure.

FIG. 5 shows the embodiment of FIG. 5 in a different position betweenthe vehicle and the platform.

DETAILED DESCRIPTION

FIG. 1 shows a vehicle 1 with a two-wing door 2 and a retractable step3. A “detection space” 4, that is a space which is to be monitored by adevice, according to the present disclosure, for risk of collision ortrapping during the extension of the retractable step 3, is illustratedbelow the retractable step 3 by dashed lines.

The positioning and significance of detection space 4 are apparent byviewing FIGS. 1 and 2. FIG. 2 shows a platform 5 as it is intendednormally to extend with its surface and its side wall in relation to thevehicle 1. Between the platform 5 and the vehicle 1 there is a gap 6.Such a gap 6 may exist in curved track sections and which gap 6 may alsobe significantly wider than shown. A safe overcoming or overclimbing ofsuch gaps 6 is provided by retractable step 3.

FIG. 3 shows platform 5 on an enlarged scale. In FIG. 3, a strip 7 isprovided according to the present disclosure and comprises a rotatableflap, that could also be a bracket or a bracket displaced in a guide,which extends over an entire length L (see FIG. 1) of the retractablestep 3 . Strip 7 is located essentially below a leading edge 8 of theretractable step 3 when said flap is extended in its activated position,as illustrated in FIG. 3.

The dashed line below the retractable step 3 again indicates thedetection space 4. Detection space 4 is the space over which a loweredge 13 of the strip 7 brushes during its extension in the direction Aof the double arrow E-A. If, during the extension operation, the frontedge 9 of the strip 7 impacts at any point along the length L against anobject, this impact is established or detected by at least one sensor.The at least one sensor may measure an angle between the strip 7 and thestep 3, for example, angle a as shown in FIG. 3. The at least one sensormay be arranged in a bearing 10 between the strip 7 and the retractablestep 3. After a detection, measures or actions are taken by an operator.After reaching an end position of the retractable step 3, the strip 7folds away and releases or no longer defines the detection space 4.

FIG. 4 shows another embodiment of a retractable step 3 having a strip7′. The strip 7′ is lowered downward about a joint 10′. A slidingmovement would be possible in a similar manner. The movement of thestrip 7′ between the active position shown and a position in which thestrip 7′ is placed against the retractable step 3 or pushed intorecesses (not shown) in a contour (not shown) of the retractable step 3is brought about by dead weight and/or by assistance by a spring force(not shown). An active movement by a servomotor or the like is alsopossible.

FIG. 5 shows a situation which may arise during the extension of theretractable step 3, of FIG. 4. A height position of the vehicle 1relative to platform upper edge 11 is too low, with the result that thestrip 7′ impacts with its front edge 9′ against vertical front 12 of theplatform 5 below platform upper edge 11. This is also established ordetected by a position sensor in the joint 10′ and results in thespecified reaction, as mentioned above. The same happens if the strip 7′impacts against a different obstacle (not shown). Instead of theposition sensor in the joint 10′, a force sensor may be arrangeddirectly on the front edge 9′ of the strip 7′.

The present disclosure is not restricted or limited to the exemplaryembodiments described and disclosed. It is possible to design the frontedges 9, 9′ themselves as sensors, whether by these edges 9, 9′ carryingprofiles which are designed as electric switching strips or which arefilled with gas. In the case of the gas, a rising gas pressure whenrunning onto an object is measured and established. Or, the strips 7, 7′may comprise two parts which are movable with respect to each other andthe movement of these parts with respect to each other is used as ameasure of the striking against an obstacle.

It is important that a strip 7, 7′ is arranged in the region below theleading edge 8 of the retractable step 3 and over the entire length 11of the retractable step 3. It is also important that the load acting onstrip 7, 7′ in its entirety and/or the position of the strip 7, 7′ isestablished by a sensor, and that, if a specified value is exceeded, themovement of the retractable step 3 is stopped and, if appropriate, analarm is triggered.

Although the present disclosure has been described and illustrated indetail, it is to be clearly understood that this is done by way ofillustration and example only and is not to be taken by way oflimitation. The scope of the present disclosure is to be limited only bythe terms of the appended claims.

1. A retractable step for the entering and exiting of vehicles (1),particularly rail vehicles, with a surface which can be walked upon, aretractable step (3), being extended from the vehicle essentially in alinear direction in order to bridge the gap (6) between the vehicle (1)and the platform (5) or the like, the retractable step comprising adevice with at least one sensor, which is intended to prevent acollision with objects during the extension operation, characterized inthat the device is a strip (7, 7′) which is connected movably to theretractable step (3), extends essentially over the entire length (L) ofthe retractable step and, in the activated state, is located essentiallyunder the leading edge (8) of the retractable step (3), and comprises atleast one sensor which detects either the position of the strip (7, 7′)relative to the retractable step or the force transferred from the stripto the retractable step.
 2. The retractable step as claimed in claim 1,characterized in that the strip (7) is a rotatable flap.
 3. Theretractable step as claimed in claim 1, characterized in that the strip(7′) is a rotatable bracket.
 4. The retractable step as claimed in claim1, characterized in that the strip is a bracket which can be displacedin a guide.
 5. The retractable step as claimed in claim 2 or 3,characterized in that the sensor measures an angle between the strip (7,7′) and the retractable step.
 6. The retractable step as claimed in oneof claims 1 to 4, characterized in that the sensor is fitted to thefront edge (9, 9′) of the strip.